GILEAD SCIENCES, INC. 333 LAKESIDE DRIVE FOSTER CITY, CALIFORNIA94404

650 574 3000 T800 445 3235

650 578 9264 F

WWW.GILEAD.COM

GILEAD SCIENCES ANNUAL REPORT 2012

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Gilead Sciences is a biopharmaceutical company that discovers, develops and commercializes innovative therapeutics in areas of unmet medical need. The company’s mission is to advance the care of patients suffering from life-threatening diseases worldwide. Headquartered in Foster City, California, Gilead has operations in North America, Europe and Asia Pacific.

AmBisome, Cayston, Complera, Emtriva, Eviplera, Gilead, Gilead Sciences, the Gilead logo design, Hepsera, Letairis, Ranexa, Stribild, Truvada, Viread, Vistide and Volibris are registered trademarks of Gilead Sciences, Inc. or one of its related companies. Atripla is a registered trademark of Bristol-Myers Squibb & Gilead Sciences, LLC. Lexiscan is a registered trademark of Astellas U.S. LLC. Tamiflu is a registered trademark of Hoffmann-La Roche Inc. Macugen is a registered trademark of Eyetech, Inc.

Full U.S. prescribing information for Gilead products is available at www.gilead.com.

WE ARE INSPIRED BY THE OPPORTUNITY TO ADDRESS UNMET MEDICAL NEEDS FOR PATIENTS WITH LIFE-THREATENING DISEASES AROUND THE WORLD.

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COVER:Katie has been living with HIV since she was an infant. Growing up in Maryland, she faced stigma at a very young age because of her disease. Despite this experience, she maintains a positive outlook on life, which she credits to her supportive family and friends. Because she knows first-hand the importance of support for people facing serious health challenges, Katie plans to devote her career to helping those in need. She recently graduated from the University of Central Florida and aims to pursue a master’s degree in public health.

WELCOME TOGILEAD.

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STRIBILD

New Tools for HIV PreventionIn July 2012, Truvada® became the first product approved by FDA in combination with safer sex practices to reduce the risk of HIV in uninfected adults at high risk, a strategy called pre-exposure prophylaxis (PrEP). At the 2012 International AIDS Conference—the largest gathering of scientists, clinicians, public health experts and advocates committed to eradicating the disease—a sense of growing optimism prevailed. The approval of Truvada for PrEP was noted as a milestone that could help slow the spread of HIV in communities at greatest risk, offering new hope for bringing the epidemic under control. While great progress in diagnosis and linkage to care for individuals with HIV has occurred in the last several years, HIV prevention remains a challenge around the world.

Jamie was diagnosed with HIV in 2008. In order to cope with the fear he experienced at the time of his diagnosis, Jamie educated himself extensively about the disease and worked closely with his doctor to find the right treatment. With his doctor’s encouragement, he began antiretroviral therapy right away. Today, among many other interests, Jamie maintains a passion for travel and the outdoors—recently visiting a small fishing village in Mexico and Patagonia.

Stribild® Approved for HIV

Because of their effectiveness, safety profiles and convenience, single tablet regimens have become a standard of care for HIV. A single tablet regimen combining the multiple drugs required for HIV treatment helps ensure patients take all of their medicine, avoiding partial doses which can lead to resistance to therapy. To this end, in 2012 we achieved a significant milestone: the approval by the U.S. Food and Drug Administration (FDA) of Stribild, a fixed-dose formulation of four Gilead medicines in a once-daily pill for treatment-naïve patients. It’s our third single tablet regimen for HIV, joining Atripla® and Complera,® which are among the most-prescribed antiretroviral regimens in the United States and Europe.

DEDICATION:HIV/AIDS AT .A TURNING POINT

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SOFOSBUVIR

Edward Gane, MD, Professor of Medicine at the University of Auckland, New Zealand, is a leading expert on treating chronic hepatitis C. As the principal investigator of the ELECTRON study of Gilead’s investigational agent sofosbuvir, Dr. Gane is excited by the potential of all-oral regimens that could make treatment more effective and tolerable for patients.

*HCV RNA undetectable four weeks after completing therapy.

Accelerating Clinical DevelopmentFollowing the acquisition of Pharmasset in January 2012, we moved quickly to expand clinical testing of hepatitis C therapies. Phase 3 trials exploring sofosbuvir in various combinations with other agents in genotype 1-6 patient populations are ongoing. In 2012, there were 21 new studies initiated, enrolling more than 2,680 participants, and because of patient and provider interest, we were able to complete enrollment of some of these trials within weeks. In addition to evaluating multiple hepatitis C drug combinations in diverse genotypes and patient populations, we are investigating ways to shorten therapy from one year to a matter of weeks.

Transforming Treatment Paradigms

Current interferon-based regimens available for treating hepatitis C remain a challenge for patients due to safety issues, side effects, variable response rates and burdensome injections. Because of this, Gilead is advancing the development of all-oral hepatitis C medicines with the goal of improving tolerability and convenience and increasing cure rates. In November 2012, we reported a 100 percent sustained virologic response rate (SVR4*) for treatment-naïve genotype 1 hepatitis C patients enrolled in a Phase 2 trial evaluating an all-oral combination of sofosbuvir (GS-7977) and ledipasvir (GS-5885) with ribavirin. Based on these data, sofosbuvir and ledipasvir have been co-formulated into a single pill, which is now being studied in Phase 3 trials.

INNOVATION:NEW TREATMENT OPTIONS FOR CHRONIC HEPATITIS C

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CHRONIC LYMPHOCYTIC LEUkEMIA

Tessa St. Rose is a Clinical Research Coordinator at Stanford University, where she helps people with serious blood cancers enroll in research studies of investigational therapies. Driven by the potential to help patients and their families at a critical time, she sees her role as an essential bridge between her patients and the often-complex clinical trial process. Tessa works closely with her patients to answer questions, explain research protocols and schedule study visits—all important steps in the search to find new treatments for today and in the future.

Improving Patient OutcomesAt Gilead, we are developing new treatment options that may target a range of cancers. We are also exploring the utility of medications used as combination therapy for diseases that are among the most difficult to treat. Our work is informed by a robust understanding of biology and focuses on interrupting key pathways involved in the formation and replication of cancerous cells.

Insights from Molecular Biology

Scientific understanding of the biological mechanisms underlying cancer is rapidly increasing—and this understanding is leading to potential breakthroughs in therapy. One area of focus at Gilead involves investigational new agents that specifically target intracellular signaling pathways responsible for tumor growth. Another approach involves targeting the extracellular matrix, which supports the system that helps enable solid tumor growth. Importantly, certain targeted agents may have fewer side effects than conventional treatments, such as chemotherapy.

Image colors have been modified.

ExCELLENCE:SEEkING TO IMPROVE TREATMENT FOR CANCER

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2012 was an exceptional year for Gilead Sciences. The company achieved revenues of $9.7 billion, including product sales of $9.4 billion, and delivered its medicines to a record number of people with serious diseases around the world. Importantly, significant progress was made advancing R&D programs across our therapeutic areas.

June 22, 2012 marked the 25th anniversary of Gilead’s founding. The company has grown rapidly from a biotech start-up to a multi- national biopharmaceutical company with over 5,000 employees spanning 26 countries on four continents. The organization is inspired by the opportunity to address the needs of patients and those involved in improving patient care: patients like katie (cover) and Jamie (page 3), physicians like Edward Gane (page 5), and healthcare providers such as Tessa St. Rose (page 7).

HIV/AIDS

Scientific advancements—in drug design, formulation and delivery—and public health advancements—in disease awareness, screen-ing and linkage to care—collectively have stemmed the global HIV/AIDS epidemic. This is a remarkable statement to make—30 years into the AIDS pandemic, and after 30 million

lives lost. At the International AIDS Conference in Washington, DC in July 2012, a new optimism emerged, fueled by improvements in HIV pre-vention, diagnosis and care around the world.

Gilead remains at the forefront of advancing HIV treatment through the development of new single tablet regimens. In August 2012, the U.S. Food and Drug Administration (FDA) approved Stribild,® the company’s third single tablet regimen. Stribild combines four medi-cations into a complete HIV treatment regimen in a once-daily pill. This approach helps allow patients to adhere to a fully suppressive course of therapy more easily and consis-tently, which is critical for the successful management of the disease. Our commercial organization introduced the product imme-diately following its approval. In 2012, Stribild, along with Atripla® and Complera,® achieved close to $4 billion in product sales.

The long-term goal is to ensure that all HIV patients, working with their prescribers, have the option to choose a single tablet regimen that may be right for them. Important progress was made in the development program for tenofovir alafenamide (TAF; GS-7340), a nucleotide reverse transcriptase inhibitor. TAF may be able to exhibit greater antiviral

efficacy than Viread® at a dose that is 10 times lower, which could help to improve tolerability of therapy. Interim findings from an ongoing Phase 2 study showed that a TAF-containing single tablet regimen achieved a similar virologic response to Stribild. In early 2013, we initiated the first Phase 3 study evaluating TAF as part of a single tablet regimen.

In July 2012, the U.S. FDA approved Truvada® for pre-exposure prophylaxis (PrEP)—marking the first time a product has been approved for reducing the risk of HIV infection in high-risk adults in combination with safer sex practices. This key advancement in the fight against HIV was the result of decades of work involving investigators, academic and medical institutions, funding agencies and more than 20,000 clinical trial participants around the world.

In addition to clinical interventions such as PrEP, Gilead continued to support educa-tion and outreach to increase access to HIV testing and care worldwide. Our partners have conducted more than 300,000 HIV tests, which represents an important contribution to public health by helping to diagnose infected individuals and connect them to care. In November 2012, the U.S. Preventive Services Task Force recommended routine HIV testing

TO OURSTOCkHOLDERS,EMPLOYEES& FRIENDS:

Left to right: Gregg H. Alton, Executive Vice President, Corporate and Medical Affairs; kevin Young CBE, Executive Vice President, Commercial Operations; Robin L. Washington, Senior Vice President and Chief Financial Officer; John C. Martin, PhD, Chairman and Chief Executive Officer; Norbert W. Bischofberger, PhD, Executive Vice President, Research and Development and Chief Scientific Officer; katie L. Watson, Senior Vice President, Human Resources; John F. Milligan, PhD, President and Chief Operating Officer

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In the area of oncology, the company is advancing novel therapies that target key molecular signaling pathways and the extracellular matrix involved in the growth and survival of certain cancers for which exist-ing treatment options are limited. Idelalisib (GS-1101), a PI3k delta inhibitor, is currently being evaluated in Phase 3 studies for indo-lent non-Hodgkin’s lymphoma and chronic lymphocytic leukemia. Simtuzumab is also progressing through Phase 2 studies to assess its safety and efficacy in treating pancreatic and colorectal cancer, myelofibrosis and certain fibrotic diseases. With the recent com-pletion of the YM BioSciences acquisition, the selective JAk inhibitor momelotinib (GS-0387/CYT-387) was added to a growing oncology and inflammation pipeline. A Phase 3 study of momelotinib in myelofibrosis is planned for the second half of 2013.

Increasing Access

Because many patients around the globe do not have the resources to obtain the medi-cines they need, we work to expand treatment access wherever possible. The company’s comprehensive patient assistance programs provide medicines in the United States at no cost for low-income, uninsured patients, and co-pay assistance coupon programs help those unable to afford the co-payments associated with commercial health insurance programs.

Gilead is also expanding access to its medications in resource-limited parts of the world—including developing countries where the HIV/AIDS epidemic is affecting millions of people. As of December 2012, approximately 3.5 million patients in the developing world were receiving one of Gilead’s HIV medicines, more than doubling the number of patients reached since 2010.

Closing

In summary, the organization has a strong business foundation, with over $9 billion in revenues in 2012. And, we continue to make significant progress in advancing new thera-pies to solidify our future growth.

I would like to thank our employees for their commitment to excellence and hard work. I also would like to acknowledge the invaluable input of our Board of Directors.

Thank you for your continued support. We look forward to the year ahead—and to the progress we believe we can make for many more patients around the world.

John C. Martin, PhDChairman and Chief Executive Officer

Forward-Looking StatementThis Annual Report includes forward-looking statements regarding our clinical studies and product candidates, including the anticipated timing and achievement of certain development milestones, regulatory filings and launches. Such statements are predictions and involve risks and uncertainties such that actual results may differ materially. Please refer to Gilead’s Annual Report on Form 10-k for the year ended December 31, 2012 attached to this report for the risks and uncertainties affecting Gilead’s business. Gilead disclaims any obligation to update any forward-looking statements in this report.

for adolescents and adults ages 15–65, and will require that private insurers cover the cost of screening.

Liver Diseases

With the Pharmasset acquisition completed in January 2012, a leadership position was established in the drug development for chronic hepatitis C virus (HCV) infection. Over the last year we have advanced the nucleo-tide NS5B inhibitor sofosbuvir (GS-7977) and a once-daily fixed-dose combination tablet containing sofosbuvir and the NS5A inhibitor ledipasvir (GS-5885) into Phase 3 testing. Our goal is to transform the paradigm of HCV care by developing an all-oral treatment regimen that has higher cure rates, better tolerability and greater convenience for patients than currently available options.

In November 2012, the first data showing the efficacy of sofosbuvir and ledipasvir plus riba-virin were presented at The Liver Meeting, the annual conference of the American Associa-tion for the Study of Liver Diseases. Interim results from a Phase 2 study suggested that a 12-week course of these medicines in patients infected with genotype 1 HCV—the most com-mon strain in the United States and the most difficult to treat—resulted in 100 percent of

participants (n=25) remaining HCV RNA unde-tectable four weeks after completing therapy (SVR4). Phase 3 trials exploring sofosbuvir in various combinations in genotype 1-6 patient populations are ongoing. Initial regulatory filings are expected in the first half of 2013, and the appropriate commercial infrastructure is now being assembled to support the potential launch of sofosbuvir.

Also at The Liver Meeting, six-year clinical trial data for Viread for the treatment of chronic hepatitis B virus (HBV) infection was present-ed, which showed sustained virological and biochemical responses among patients, with no evidence of viral resistance. These results reinforce Viread ’s position as the most-pre-scribed medicine for chronic HBV in the United States and most European countries.

Cardiovascular, Respiratory & Oncology/Inflammation

Across therapeutic areas, we look for ways to appropriately expand the use of available medicines and to advance investigational therapies to address the unmet needs of patients. In cardiovascular disease, Ranexa,® an oral late sodium current inhibitor that is currently indicated for chronic angina, is also being explored in Phase 3 studies for type 2

diabetes. In addition, a new generation of late sodium current inhibitors are being developed, such as GS-6615, which is currently in Phase 1 studies and has the potential to treat ischemic heart disease and arrhythmias. In the area of pulmonary arterial hypertension (PAH), a Phase 4 research program has been designed to advance the understanding of the disease pathology and further define the clinical profile of Letairis,® including the potential for the product to be used in combination with another oral PAH treatment as frontline therapy.

In the area of respiratory disease, Cayston,® an inhaled antibiotic approved to treat cystic fibrosis (CF) patients with Pseudomonas aeruginosa, is being evaluated in Phase 3 studies to assess its efficacy in treating bacterial infections associated with non-CF bronchiectasis. Results from these trials are expected in 2013.

In addition, we are evaluating GS-5806 in Phase 2 clinical trials. This compound has been shown in preclinical studies to block respiratory syncytial virus (RSV). RSV is a pathogen that infects the human respiratory tract, leading to bronchiolitis and pneumonia. It is estimated that 125,000 newborns are hospitalized with RSV every year in the United States.

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Roberto Tascione, General Manager, Italy, Gilead Sciences

EU MARKETING APPROVAL SUBMITTEDSTRIBILD® (ELVITEGRAVIR 150MG/COBICISTAT 150MG/EMTRICITABINE 200MG/TENOFOVIR DISOPROxIL FUMARATE 300MG) POTENTIAL INDICATION: HIV/AIDS

U.S. AND EU MARKETING APPROVALS SUBMITTED COBICISTAT (PHARMACOkINETIC ENHANCER) POTENTIAL INDICATION: HIV/AIDS

ELVITEGRAVIR (INTEGRASE INHIBITOR) POTENTIAL INDICATION: HIV/AIDS

PHASE 3SINGLE TABLET REGIMEN OF ELVITEGRAVIR/COBICISTAT/EMTRICITABINE/TENOFOVIR ALAFENAMIDE POTENTIAL INDICATION: HIV/AIDS

PHASE 2SINGLE TABLET REGIMEN OF DARUNAVIR/COBICISTAT/EMTRICITABINE/TENOFOVIR ALAFENAMIDE POTENTIAL INDICATION: HIV/AIDS

Gilead is working to develop the next generation of HIV

single tablet regimens that are effective, tolerable and

convenient and that may provide certain advantages

over existing treatment options. This is particularly

important as more individuals with HIV are diagnosed

and brought into care, because life-long treatment is

required to control the virus.

We are conducting clinical trials of tenofovir alafen-

amide (TAF; GS-7340); TAF may be able to exhibit greater

antiviral efficacy than Viread® at a dose that is 10 times

lower, which may improve the tolerability of HIV therapy.

Phase 3 studies will examine a once-daily single tablet

regimen of TAF, Emtriva,® the integrase inhibitor

elvitegravir and the boosting agent cobicistat, compared

to Stribild® among patients new to HIV therapy.

While HIV medicines reduce the level of virus in the

blood to undetectable levels, the ultimate goal is to

develop a cure. Gilead scientists are engaged in early-

stage research to identify novel therapeutic agents that

may help eradicate HIV infection.

FOCUS AREAHIV/AIDS

FINANCIAL HIGHLIGHTS

* The earnings per share calculations for all periods presented reflect the two-for-one stock split effective on January 25, 2013.

• Non-GAAP diluted earnings per share for 2010 exclude the impact of after-tax acquisition-related expenses of $0.08, restructuring expenses of $0.02 and stock-based compensation expenses of $0.08.

• Non-GAAP diluted earnings per share for 2011 exclude after-tax acquisition-related expenses of $0.05 and stock-based compensation expenses of $0.09.

• Non-GAAP diluted earnings per share for 2012 exclude after-tax acquisition-related expenses of $0.08, restructuring expenses of $0.01 and stock-based compensation expenses of $0.22.

EARNINGS PER SHARE

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GAAP DILUTED EARNINGS PER SHARE NON-GAAP DILUTED EARNINGS PER SHARE*

$ 2.00 –

$ 1.75–

$ 1.50–

$ 1.25 –

$ 1.00 –

$ .75 –

$ .50 –

$ .25 –

$ 0 –

PRODUCT SALES($ IN MILLIONS)

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$10,000 –

$ 9,000 –

$ 8,000 –

$ 7,000 –

$ 6,000 –

$ 5,000 –

$ 4,000 –

$ 3,000 –

$ 2,000 –

$ 1,000 –

$ 0 –

OTHERAMBISOMERANEXALETAIRISANTIVIRALFRANCHISE

TOTAL REVENUES($ IN MILLIONS)

10 11 12

$10,000 –

$ 9,000 –

$ 8,000 –

$ 7,000 –

$ 6,000 –

$ 5,000 –

$ 4,000 –

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$ 0 –

OPERATING CASH FLOW($ IN MILLIONS)

$ 4,000 –

$ 3,500 –

$ 3,000 –

$ 2,500 –

$ 2,000 –

$ 1,500 –

$ 1,000 –

$ 500 –

$ 0 –

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Rico Calara, PhD, Associate Director, Medical Sciences, Gilead SciencesJanelle Goins, PharmD, Associate Director, Medical Sciences, Gilead Sciences

PHASE 3RANOLAZINE (LATE SODIUM CURRENT INHIBITOR) POTENTIAL INDICATION: INCOMPLETE REVASCULARIZATION POST-PCI

RANOLAZINE (LATE SODIUM CURRENT INHIBITOR) POTENTIAL INDICATION: TYPE 2 DIABETES

PHASE 2 RANOLAZINE/DRONEDARONE FIXED-DOSE COMBINATION POTENTIAL INDICATION: PAROxYSMAL ATRIAL FIBRILLATION

PHASE 1GS-6615 POTENTIAL INDICATIONS: ISCHEMIC HEART DISEASE AND ARRHYTHMIAS

Cardiovascular disease and diabetes each represent a

considerable public health burden worldwide. There is

a significant unmet medical need for new therapeutic

options for patients living with these conditions.

A number of clinical studies are ongoing to explore

uses for Ranexa,® currently indicated for the treatment

of chronic angina, that may potentially benefit specific

populations of patients. This includes a study evaluating

Ranexa in patients with both chronic angina and type 2

diabetes. Additional clinical trials are evaluating Ranexa

in patients unable to control type 2 diabetes with

currently available medications and in patients who

have undergone stenting procedures.

We are working to identify potential new therapies for

cardiovascular disease by exploring the mechanism of

action underlying Ranexa—inhibition of the late sodium

current. This research has led us to a Phase 2 clinical

study evaluating Ranexa in combination with drone-

darone for paroxysmal atrial fibrillation and to identify

the novel molecule GS-6615 that may have potential to

treat various cardiovascular diseases, such as ischemic

heart disease and arrhythmias.

Even with the advancements of pulmonary arterial

hypertension treatments such as Letairis,® there is a

need to further optimize the use of existing agents.

Because of this, Gilead continues to conduct Phase 4

studies to answer questions about optimal patient care

and further define the clinical benefit of Letairis

in broader patient populations.

FOCUS AREACARDIOVASCULARDISEASE

Diana Brainard, MD, Senior Director, Clinical Research, Liver Diseases, Gilead SciencesPhil Pang, MD, Director, Clinical Research, Liver Diseases, Gilead Sciences

CHRONIC HEPATITIS C

PHASE 3SOFOSBUVIR (NUCLEOTIDE NS5B INHIBITOR) SINGLE TABLET REGIMEN OF SOFOSBUVIR AND LEDIPASVIR (NUCLEOTIDE NS5B INHIBITOR/NS5A INHIBITOR)

PHASE 2GS-9451 (NS3 PROTEASE INHIBITOR) GS-9669 (NON-NUCLEOSIDE NS5B INHIBITOR) GS-5816 (PAN-GENOTYPIC NS5A INHIBITOR)

PHASE 1GS-9620 (TLR-7 AGONIST)

CHRONIC HEPATITIS B

PHASE 1GS-9620 (TLR-7 AGONIST) TENOFOVIR ALAFENAMIDE (NUCLEOTIDE REVERSE TRANSCRIPTASE INHIBITOR)

LIVER FIBROSIS DUE TO NONALCOHOLIC STEATOHEPATITIS OR PRIMARY SCLEROSING CHOLANGITIS

PHASE 2SIMTUZUMAB* (MONOCLONAL ANTIBODY)

* Formerly GS-6624

Chronic hepatitis B and C are caused by persistent viral

infections, and can frequently lead to liver cirrhosis, liver

failure and cancer.

Chronic hepatitis B can be treated using Viread,® which

in one ongoing clinical study showed a regression of

cirrhosis after five years of therapy in approximately 75

percent of patients for whom baseline liver biopsy data

were available. For most patients with chronic hepati-

tis B, life-long antiviral therapy is required. Because of

this, we continue to research combination approaches

to increase cure rates in chronic hepatitis B patients,

including oral medicines and therapeutic vaccines.

Gilead is also advancing a broad and diverse pipeline of

investigational treatments for chronic hepatitis C, with

the ultimate goal of developing an all-oral regimen that

works across all strains of the virus and which results

in high cure rates with a shorter treatment duration

than today’s therapies. We have completed four Phase 3

studies of sofosbuvir (GS-7977) as a single agent admin-

istered with standard of care therapies. Positive results

from these trials were announced in late 2012 and early

2013, and will support initial regulatory applications for

the compound in 2013. Additionally, we have developed

a once-daily fixed-dose combination of sofosbuvir with

ledipasvir (GS-5885), which is now in Phase 3 studies.

People living with chronic hepatitis C often have

other viral diseases, including HIV, and many patients

await liver transplantation. Because of this, we are

also evaluating hepatitis C treatments in diverse and

difficult-to-treat patient groups.

FOCUS AREALIVER DISEASES

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Derek Marshall, Research Scientist, Biology, Gilead SciencesVivian Barry, Associate Scientist, Biology, Gilead SciencesRhyannon Spangler, Senior Research Associate, Biology, Gilead Sciences

PHASE 3IDELALISIB (PI3k DELTA INHIBITOR) POTENTIAL INDICATION: CHRONIC LYMPHOCYTIC LEUkEMIA

IDELALISIB (PI3k DELTA INHIBITOR) POTENTIAL INDICATION: INDOLENT NON-HODGkIN’S LYMPHOMA

PHASE 2MOMELOTINIB (JAk INHIBITOR) POTENTIAL INDICATION: MYELOFIBROSIS

SIMTUZUMAB (MONOCLONAL ANTIBODY) POTENTIAL INDICATION: MYELOFIBROSIS

SIMTUZUMAB (MONOCLONAL ANTIBODY) POTENTIAL INDICATION: PANCREATIC CANCER

SIMTUZUMAB (MONOCLONAL ANTIBODY) POTENTIAL INDICATION: COLORECTAL CANCER

GS-9820 (PI3k DELTA INHIBITOR) POTENTIAL INDICATION: LYMPHOID MALIGNANCIES

PHASE 1GS-9973* (SYk INHIBITOR) POTENTIAL INDICATION: B-CELL MALIGNANCIES * Being developed as a single agent and in combination with idelalisib.

Oncology and inflammation are newer focus areas for

Gilead. We are making rapid progress in identifying

targeted investigational cancer therapies and evaluating

them in clinical studies.

Our lead oncology candidates include idelalisib (GS-

1101) and momelotinib (GS-0387/CYT-0387). Idelalisib

is a small molecule drug designed to inhibit the PI3k

delta signaling pathway that is thought to drive certain

cancer cell development. The compound is being stud-

ied in clinical trials for chronic lymphocytic leukemia

and indolent non-Hodgkin’s lymphoma. Momelotinib is

an investigational JAk inhibitor that has shown promise

for the treatment of myelofibrosis, a blood disorder. This

molecule was added to Gilead’s development pipeline

through the acquisition of YM BioSciences.

Simtuzumab (GS-6624) is the first monoclonal antibody

developed to target LOxL2, an enzyme thought to be

involved in solid tumor growth. It is being studied for

pancreatic and colorectal cancers and myelofibrosis.

In addition, GS-9973, our SYk inhibitor, is in clinical

studies for B-cell malignancies.

Through partnerships, we are exploring new therapeutic

targets in oncology. Our multi-year collaboration with

Yale School of Medicine is searching for the genetic

basis and underlying molecular mechanisms of many

forms of cancer.

FOCUS AREAONCOLOGY/INFLAMMATION

Anne Mathew, Director, Marketing, Gilead Sciences

PHASE 3AZTREONAM FOR INHALATION SOLUTION POTENTIAL INDICATION: NON-CF BRONCHIECTASIS

PHASE 2SIMTUZUMAB (MONOCLONAL ANTIBODY) POTENTIAL INDICATION: IDIOPATHIC PULMONARY FIBROSIS

GS-5806 POTENTIAL INDICATION: RESPIRATORY SYNCYTIAL VIRUS

Gilead’s first product in the category of respiratory

disease, Tamiflu,® remains the leading antiviral for

treatment and prevention of seasonal influenza.

Our inhaled antibiotic, Cayston,® is indicated to treat

respiratory Pseudomonas aeruginosa in people with

cystic fibrosis (CF), an inherited disease that affects

the lungs and digestive system. We are also investigating

the potential for Cayston to treat bacterial infections in

people with non-CF bronchiectasis.

Simtuzumab (GS-6624) is a monoclonal antibody being

investigated for the potential treatment of idiopathic

pulmonary fibrosis, a life-threatening scarring of the

lungs that has no known cause. GS-5806 is being studied

for respiratory syncytial virus (RSV), which infects the

human respiratory tract and can lead to bronchiolitis

and pneumonia. RSV is the most common microbial

cause of lung and airway infections in infants and

young children.

FOCUS AREARESPIRATORY DISEASE

1716

EMTRIVA®

EMTRICITABINE

HIV/AIDS

JAPAN TOBACCO INC. (JAPAN)

ATRIPLA® EFAVIRENZ 600 MG/EMTRICITABINE 200 MG/TENOFOVIR DISOPROxIL FUMARATE 300 MG

HIV/AIDS

BRISTOL-MYERS SQUIBB COMPANY (U.S., WESTERN EUROPE, CANADA) MERCk & CO., INC. (REST OF WORLD)

STRIBILD® ELVITEGRAVIR 150MG/COBICISTAT 150MG/ EMTRICITABINE 200MG/TENOFOVIR DISOPROxIL FUMARATE 300MG

HIV/AIDS

JAPAN TOBACCO INC. (JAPAN)

VIREAD® TENOFOVIR DISOPROxIL FUMARATE

HIV/AIDS

JAPAN TOBACCO INC. (JAPAN)

VIREAD® TENOFOVIR DISOPROxIL FUMARATE

CHRONIC HEPATITIS B

JAPAN TOBACCO INC. (JAPAN)COMPLERA®

EMTRICITABINE/RILPIVIRINE/TENOFOVIR DISOPROxIL FUMARATE

HIV/AIDS

JANSSEN R&D IRELANDMARkETED AS EVIPLERA® IN EUROPE

TRUVADA® EMTRICITABINE/TENOFOVIR DISOPROxIL FUMARATE

HIV/AIDS

JAPAN TOBACCO INC. (JAPAN)

HEPSERA®

ADEFOVIR DIPIVOxIL

CHRONIC HEPATITIS B

GLAxOSMITHkLINE INC. (CHINA, JAPAN, SAUDI ARABIA)

LExISCAN® REGADENOSON INJECTION

CORONARY VASODILATION

ASTELLAS PHARMA INC. (U.S., CANADA)RAPIDSCAN (EUROPE AND SELECT OTHER MARkETS)

LETAIRIS®

AMBRISENTAN

PULMONARY ARTERIAL HYPERTENSION (WHO GROUP 1)

GLAxOSMITHkLINE INC. MARkETED AS VOLIBRIS® OUTSIDE OF THE U.S.

RANExA® RANOLAZINE

CHRONIC ANGINA

MENARINI GROUP (EUROPE)

CAYSTON®

AZTREONAM FOR INHALATION SOLUTION

CYSTIC FIBROSIS, P. AERUGINOSA

TAMIFLU® OSELTAMIVIR PHOSPHATE

INFLUENZA A & B

F. HOFFMANN-LA ROCHE LTD(WORLDWIDE)

MACUGEN®

PEGAPTANIB SODIUM INJECTION

NEOVASCULAR (WET) AGE-RELATED MACULAR DEGENERATION

EYETECH, INC. (U.S.)PFIZER INC. (OUTSIDE U.S.)

VISTIDE®

CIDOFOVIR INJECTION

CMV RETINITIS IN PATIENTS WITH AIDS

AMBISOME® AMPHOTERICIN B LIPOSOME FOR INJECTION

SEVERE FUNGAL INFECTIONS

ASTELLAS PHARMA INC. (U.S., CANADA)DAINIPPON SUMITOMO PHARMA CO., LTD. (JAPAN)

OTHERCARDIOVASCULAR

RESPIRATORYLIVER DISEASEHIV/AIDS

MARkETEDPRODUCTS

Images shown do not represent actual size.

ACCESS HIGHLIGHTS

• Three and a half million HIV patients in 130 low- and middle-income countries are receiving Gilead therapies—representing approximately one-third of people being treated for HIV in these countries.

• 15 Indian manufacturers and one South African manufacturer have been licensed to produce generic versions of our HIV and chronic hepatitis B medicines for developing countries.

• Half of all people in the United States taking Gilead HIV medicines receive them through federal and state programs at substantially discounted prices.

Advancing therapies for life-threatening diseases

requires innovation—not just in the laboratory but also

in how medicines are delivered to patients. We make it

a priority to ensure that people who need our therapies

have access, regardless of their ability to pay or where

they live in the world.

Ensuring Access in Developing World Countries

Many of the diseases our medicines treat place the

greatest burden on developing world countries with

the fewest resources. To address this challenge, Gilead

works with more than 70 manufacturers, regional and

local distributors and generic licensees to lower prices

and enable generic production of certain Gilead medi-

cines for HIV/AIDS and chronic hepatitis B. In 2012,

we began transferring the technology for Stribild,® our

newest HIV single tablet regimen, so that these partners

can begin the process of producing generic versions for

patients in low- and middle-income countries. We also

coordinate and support educational activities for medi-

cal and clinical workers to ensure proper use of

our medicines.

2012 also marked the first year of a five-year expanded

partnership with the World Health Organization to

control visceral leishmaniasis (VL), the second-deadliest

parasitic disease after malaria. Gilead will provide

enough AmBisome® to treat 50,000 patients with VL.

Ensuring Access in the United States

Recognizing the financial difficulties many Americans

face in today’s economy, Gilead has established one

of the most comprehensive packages of patient assis-

tance solutions. This includes providing our medicines

to eligible patients at no charge and offering a co-pay

coupon program for patients with private insurance,

regardless of income. We also have a long history of

working with state AIDS Drug Assistance Programs

(ADAPs) to increase access to HIV treatment. A voluntary

price freeze and additional discounts for ADAPs for our

HIV medicines run through 2013.

FOCUS AREAACCESS TO TREATMENT

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BOARD OF DIRECTORSJohn C. Martin, PhDChairman and Chief Executive Officer, Gilead Sciences

James M. DennyLead Independent Director, Gilead Sciences Board of Directors

John F. Cogan, PhDSenior Fellow, Hoover Institution, Stanford University

Etienne F. DavignonMinister of State,Chairman, Genfina

Carla A. HillsChair and Chief Executive Officer,Hills & Company International Consultants

kevin E. LoftonPresident and Chief Executive Officer,Catholic Health Initiatives

John W. MadiganRetired Chairman and Chief Executive Officer, Tribune Company

Gordon E. Moore, PhDRetired Chairman and Chief Executive Officer, Intel Corporation

Nicholas G. MooreRetired Global Chairman, PricewaterhouseCoopers

Richard J. Whitley, MDDistinguished Professor, Loeb Scholar Chair in Pediatrics, Professor of Pediatrics, Microbiology, Medicine, and Neurosurgery,University of Alabama at Birmingham

Gayle Edlund WilsonFormer Chair, Ralph M. Parsons Foundation

Per Wold-OlsenRetired President, Human HealthIntercontinental Division,Merck & Co., Inc.

DIRECTOR EMERITUS, GILEAD SCIENCES BOARD OF DIRECTORSGeorge P. Shultz, PhDDistinguished Fellow, Hoover Institution, Stanford University

SENIOR LEADERSHIP TEAMJohn C. Martin, PhDChairman and Chief Executive Officer

John F. Milligan, PhDPresident and Chief Operating Officer

Norbert W. Bischofberger, PhDExecutive Vice President, Research and Development and Chief Scientific Officer

Gregg H. AltonExecutive Vice President, Corporate and Medical Affairs

kevin Young CBEExecutive Vice President, Commercial Operations

Robin L. WashingtonSenior Vice President and Chief Financial Officer

katie L. Watson Senior Vice President, Human Resources

SCIENTIFIC ADVISORY BOARDJoel R. Huff, PhD (Chairperson)Retired Vice President of Medicinal Chemistry,Merck Research Laboratories

Paul Berg, PhDCahill Professor of Biochemistry, Emeritus,Stanford University School of Medicine

Francis V. Chisari, MDProfessor of Virology and Immunology,The Scripps Research Institute

Peter B. Dervan, PhDBren Professor of Chemistry,California Institute of Technology

Paul E. klotman, MDPresident and Chief Executive Officer, John E. and Clara B. WhitmoreProfessor, Baylor College of Medicine

John W. Mellors, MDProfessor of Medicine,Chief, Division of Infectious Diseases, University of Pittsburgh School of Medicine

Eugene R. Schiff, MDLeonard Miller Professor of Medicine,Director for Schiff Liver Institute, Director for Center for Liver Diseases,University of Miami School of Medicine

Robert T. Schooley, MDProfessor of Medicine and Head, Division of Infectious Diseases,Vice Chair of Department of Medicine,University of California, San Diego

Eric J. Topol, MD Director, Scripps Translational Science InstituteChief Academic Officer, Scripps Health Professor of Genomics, The Scripps Research Institute

Bernard M. Wagner, MDEmeritus Research Professor of Pathology, New York University Medical Center

CORPORATE SECRETARYGregg H. AltonExecutive Vice President, Corporate and Medical Affairs

INDEPENDENT REGISTERED PUBLIC ACCOUNTANTS Ernst & Young LLPPalo Alto, California

CORPORATE HEADQUARTERSGilead Sciences, Inc.333 Lakeside DriveFoster City, CA 94404 USA(800) 445-3235 or (650) 574-3000www.gilead.com

STOCkHOLDER INQUIRIESInquiries from our stockholders and potential investors regarding our company are always welcome and will receive a prompt response. Please direct your requests for information to:

Investor RelationsGilead Sciences, Inc.333 Lakeside DriveFoster City, CA 94404 USA(800) 445-3235 or (650) 574-3000

Information regarding Gilead also is available at www.gilead.com.

STOCk LISTINGGilead common stock is traded on the Nasdaq Global Select Stock Market, under the symbol GILD.

ANNUAL MEETINGThe annual meeting of stockholders will be held at 10:00 a.m. on Wednesday, May 8, 2013, at the Westin San Francisco Airport Hotel.

TRANSFER AGENT AND REGISTRARCommunications concerning stock transfer requirements, lost certificates and changes of address should be directed to the Transfer Agent:

Computershare480 Washington Boulevard Jersey City, NJ 07310-1900USA(800) 710-0940www.computershare.com

EQUAL OPPORTUNITY EMPLOYERGilead Sciences is proud to be an equal opportunity employer and extends employment to men and women from culturally diverse backgrounds. Our environment respects individual differences and recognizes each employee as an integral member of our company. Our workforce reflects these values and celebrates the individuals who make up our growing team.

CORPORATEINFORMATION

GILEAD SCIENCES, INC. 333 LAKESIDE DRIVE FOSTER CITY, CALIFORNIA94404

650 574 3000 T800 445 3235

650 578 9264 F

WWW.GILEAD.COM

GILEAD SCIENCES ANNUAL REPORT 2012

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Gilead Sciences is a biopharmaceutical company that discovers, develops and commercializes innovative therapeutics in areas of unmet medical need. The company’s mission is to advance the care of patients suffering from life-threatening diseases worldwide. Headquartered in Foster City, California, Gilead has operations in North America, Europe and Asia Pacific.

AmBisome, Cayston, Complera, Emtriva, Eviplera, Gilead, Gilead Sciences, the Gilead logo design, Hepsera, Letairis, Ranexa, Stribild, Truvada, Viread, Vistide and Volibris are registered trademarks of Gilead Sciences, Inc. or one of its related companies. Atripla is a registered trademark of Bristol-Myers Squibb & Gilead Sciences, LLC. Lexiscan is a registered trademark of Astellas U.S. LLC. Tamiflu is a registered trademark of Hoffmann-La Roche Inc. Macugen is a registered trademark of Eyetech, Inc.

Full U.S. prescribing information for Gilead products is available at www.gilead.com.

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GILEAD SCIENCES, INC. 333 LAKESIDE DRIVE FOSTER CITY, CALIFORNIA94404

650 574 3000 T800 445 3235

650 578 9264 F

WWW.GILEAD.COM

GILEAD SCIENCES ANNUAL REPORT 2012

GILE

AD

SC

IEN

CE

S A

NN

UA

L RE

PO

RT 2012

Gilead Sciences is a biopharmaceutical company that discovers, develops and commercializes innovative therapeutics in areas of unmet medical need. The company’s mission is to advance the care of patients suffering from life-threatening diseases worldwide. Headquartered in Foster City, California, Gilead has operations in North America, Europe and Asia Pacific.

AmBisome, Cayston, Complera, Emtriva, Eviplera, Gilead, Gilead Sciences, the Gilead logo design, Hepsera, Letairis, Ranexa, Stribild, Truvada, Viread, Vistide and Volibris are registered trademarks of Gilead Sciences, Inc. or one of its related companies. Atripla is a registered trademark of Bristol-Myers Squibb & Gilead Sciences, LLC. Lexiscan is a registered trademark of Astellas U.S. LLC. Tamiflu is a registered trademark of Hoffmann-La Roche Inc. Macugen is a registered trademark of Eyetech, Inc.

Full U.S. prescribing information for Gilead products is available at www.gilead.com.